1. Technical Field
This invention relates to computer and facsimile transmissions, specifically a method to efficiently and reliably guarantee transmission and receipt of faxes documents from non-internet devices routed through internet connectivity based upon extrinsic circumstances: asynchronously, synchronously, pre-call phone number validation.
2. Background
The terms “facsimile” and “fax” shall be used interchangeably and refer to data that is transmitted on the protocol generically known as “T.30”.
The term “telephonic” and “telephony” shall generally be considered to be the transmission of audio signals on a PSTN (“Packet Switched Telephony Network”) according to generally accepted protocols.
The term “ATA” shall mean analog telephone adapter, which shall generally mean a device that interfaces a traditional telephone handset with a TCP/IP interface.
The term “T.30” shall generally mean a protocol for the transmission of facsimile documents that conform to the “Group-2” or “Group-3” protocol.
The term “HTTP” shall generally mean Hypertext Transfer Protocol (HTTP) which is an application layer protocol for distributed, collaborative, hypermedia information systems.
The term “SIP” shall mean the Session Initiation Protocol which is a signaling protocol, widely used for controlling multimedia communication sessions such as voice and video calls over Internet Protocol (IP). The protocol can be used for creating, modifying and terminating two-party (unicast) or multiparty (multicast) sessions consisting of one or several media streams.
The term “ITU G.729” is an ITU (International Telecommunications Union, www.itu.int) standard codec. It offers toll quality speech at a reasonably low bit rate of 8 Kbps. However, it is a rather “costly” codec in terms of CPU processing time, therefore some VoIP phones and adapters (notably the Linksys/Sipura/Cisco brands) can only handle one G.729 call (channel) at a time.
The term “PSTN” shall mean a public switched telephone network (PSTN) is the network of the world's public circuit-switched telephone networks.
The term “Media Gateway”
The communication of two telephonic devices and the ability to deliver large amount of fax data first existed in the PSTN environment where voice calls were the main consumer and fax or data communication minor consumers.
Through the use of the PSTN environment all of the same rules and regulations apply that are required for a voice call. The most notable requirement is the use of the fax machine handset to call 911 for emergency support. This 911 Act was sanctioned by the Wireless Communications and Public Safety Act of 1999 to improve public safety and facilitate prompt deployment of emergency services. The faxing mechanism is being carried on the transport mechanism of a voice phone call with tones (sounds) being converted and unconverted to data bits (1s and 0s) to transmit the fax “image” from one location to another location.
The fax protocol T.30 (the ITU standard governing how fax devices function) is the standard for the large amount of fax data communication that has an origination or destination in the PSTN environment. Inherent to the PSTN environment is the reliance and dependency on fixed latency which enables small amounts of delays or retransmission periods to continue with a reliable and accurate fax data representation on the receiving device. The process of transmitting and receiving continuous data is necessary for successful operation of processing fax data from the sender to the receiver without significant interruptions. The fax protocol T.30 has structured in it small amounts of data resend and retry period mechanisms to allow for minor interruption recovery procedural operations. This has been a very successful industry with the support, ability and accessibility to transmit and receive fax documents to be a standard operating procedure for most every business and most individuals from their homes. The ability to transmit and receive legal documents via “faxing” has been established and accepted by the world for all forms of communication and agreements. This compliance and legal document acceptance has established a set of usable expectations worldwide with this everyday use of faxing.
There is a drawback to this model of operation. The receiving fax device may or may not be able to accept the call, or even process the data if the call is accepted. This causes the user to wait and decide the next course of action. The waiting to send the fax data again is not an operation that the user wants to do. The user wants to type a phone number, fax the document and receive some form of acknowledgement of the fax transaction. An error that is commonly encountered is mistyped phone numbers. The users of the fax sending device inputs an incorrect data number causing the submission to fail without any connection being made to the target receiving fax device. Today, IP technology is widespread with the foundation and formation of the internet, intranet and world wide web (www). This highly flexible, redundant failure fallback packet switching concept has laid the ground work for the network that is in common use by all. The current implemented and accepted fax protocols used in the IP technology network: RTP, Real-time Transport Protocol (the IETF standard defined in RFC 3550); T.37 (the ITU standard governing store and forward faxing); T.38 (the ITU standard governing real-time faxing over IP networks).
The general IP traffic and bursts of IP traffic causes delay and even failure scenarios routinely with fax data transmissions. A study has demonstrated that a T1 data circuit can handle well over 40 simultaneous voice calls using today's codec's, the triple redundant packets and G.711 based call initiation phase of T.38 limits the safe number of calls to around 20. This completely reverses the cost benefits of moving to Fax data traffic in to a VoIP system, and in many cases pushes the customer over the top requiring them to purchase considerably more expensive circuits and adds more layers of indirection and complexity to their solution to include FoIP at significantly lower access numbers.
The issue with incorrect phone numbers is magnified when dealing with the IP network. There are longer delays and a higher risk of other negative impacts to the route that the packets must travel to reach the predestined receiving fax device. The originating transmitting fax device has had to either delay the data being sent (Phase D) through inserted delays and stalling mechanisms or blindly starts transmitting the large amount of fax data prior to confirmation of the destination fax device being ready and even capable of receiving the fax data transaction. Rather than error the call and cause the user to resend, the user expects the fax to be retried and sent successfully with little or no interaction required. The preference of the sender is that the fax data gets sent and notification is received after the successful transmission has completed.
Even through all of the technological advancements and various forms of moving large amounts of data, the physical process of transmitting large amounts of legal data continues to be with the use of “scan and send” fax devices. Even with the variations of sending faxes without the physical fax machine, every company still has and maintains fax machines for regular use by their employees, customers, and vendors. Even with the increased use of email, ftp, web postings, and other data accessible points the preferred legal means of transmitting large amounts of data via fax remains in high use throughout the world for many years to come.
The configuration of these media networking communication systems requires much information and configuration to obtain optimal operation and functionality by each of the individual components and on the larger system as a whole entity. This continues to be an urgent issue due to the speed and number of changes that are increasingly developed, disseminated, and implemented by all of the various vendors involved with these complex media networking systems. The integration, stability and reliability is routine in question due to the vast number of networking components involved and the amount of effort and time really necessary to prove full interoperability is successful without any degradation of the networking systems.
The “scan and send” of large amounts of data through fax devices remains a vital part of day to day operations for many businesses. The merging of this faxing data stream on to the IP network is happening through various avenues, but each mechanism has left unresolved issues for the fax users to deal with. The compliance of faxes transmitted on the IP network needs to be addressed for legality, security and status accounting purposes. The mass number of independent component vendors for the media networking communication systems causes a real problem with co-functionality and co-existing, along with the tuning of such systems for reliable, safe, secure, and the most efficient operational settings for the network system.